/* os_shm.c : os share memory operation
 * CopyRight (C) 2008 dgnbbs
 * drangon_zhou@21cn.com
 * 2008-10
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "os_shm.h"

#include <sys/shm.h>

struct os_shm_t_t
{
	void * shm;
};


os_shm_t os_shm_open( long key, int32_t size )
{
	struct os_shm_t_t * shm;
	int id;
	void * ptr;

	id = shmget( key, size, 0 );
	if( id < 0 ) {
		id = shmget( key, size, IPC_CREAT | 0660 );
		if( id < 0 ) {
			PR_ERR( "shmget create key %ld size %ld failed, errno %d", key, (long)size, errno );
			return NULL;
		}
	}
	
	ptr = shmat( id, NULL, 0 );
	if( ptr == (void*)-1 ) {
		PR_ERR( "shmat key %ld size %ld shmid %d failed, errno %d", key, (long)size, id, errno );
		return NULL;
	}

	shm = malloc( sizeof(*shm) );
	shm->shm = ptr;
	return (os_shm_t)shm;
}

int os_shm_close( os_shm_t shm )
{
	struct os_shm_t_t * myshm = (struct os_shm_t_t *)shm;
	if( shmdt( myshm->shm ) < 0 ) {
		PR_ERR( "shmdt [%p] failed, errno %d", myshm->shm, errno );
		return -1;
	}
	free( myshm );
	return 0;
}

void * os_shm_address( os_shm_t shm )
{
	return ((struct os_shm_t_t *)shm)->shm;
}

